heat index," princess Diana's beauty secrets. One of lady di's makeup artists is speaking out revealing the tricks that help make Diana so beautiful and timeless. ABC's llaama Hasan has the tips you can use right now. ? Reporter: She was one of the most photographed women in the world. Princess Diana was a glamorous global fashion icon. She was an incredibly beautiful woman. She had these amazing long limbs that went on forever. She wore clothes incredibly beautifully and was always stylish and elegant. Reporter: So how did she do it? This morning makeup art Mary Greenwell is opening up. In this amazing skin. Phone for her great skin but because she was being photographed you had to put the foundation on and concealer and eye shadow and mascara and the whole regime that would give you that polished look. But why don't I do something on you? Go I have me the royal treatment. Yeah. ? La la la I'm putting on a dress and some diamond studded shoes ? Reporter: As Greenwell is giving me the royal treatment, she spills some of Diana's beauty secrets. She realized her best features were her eyes and amazing bone structure and gorgeous skin and she was so young. Dsheidn't need a strong amount. She wanted a nude mouth and a south mouth. ? Reporter: Greenwell began working with the princess in 1991 on a "Vogue" shoot creating this timeless look. Helping princess Diana establish her signature look. This one, for example, which is very typical of what I would use on Diana sort of soft browns, muted browns, those kind of tones that are within one's own skin color to bring out her blue eyes. Reporter: As we as makeup she launched her own perfume. She always, always for fragrance always which is a huge thing in a woman's life. Reporter: So, lady, if you want to get the people's princess flawless all you need is -- Mascara without a doubt. Soft palette like this one I'm using on you right now and then probably a really good light foundation. Reporter: And as for me and my royal treatment -- Look at you. Look how beautiful you look. Thank you, you did it. It's your work. Reporter: For "Good morning America," lama Hasan, ABC news, London.

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